All posts by Iain Marshall
Below are all of Iain Marshall's postings, with the most recent are at the bottom of the page.Me
Thursday 3 February 2011 4:35AM
Hi,
I am in Exeter .
I have been having problems with the multiplexes on CH22 and CH28 (STOCKLAND HILL). CH22 is the worst where sometimes I've had no picture at all or a slideshow with sound stuttering. Even when it is perfectly watchable, if I'm recording a TV station, from ANY of the 5 multiplexes, the programs on multiplex CH22 start breaking up again. Any ideas as to why this is?
Also, according to www.digitaluk.co.uk/postcodechecker/, it gives a bearing of 72 degrees to Stockland Hill from my address and the website www.magnetic-declination.com/ states a magnetic decination of 2 degrees 41 minutes WEST, Declination is NEGATIVE and Inclination is 65 degress 43 minutes.
Therefore, should I be pointing my aerial at approx. 69 degrees instead of 72 and having it at an angle of approx 66 degrees from upright or, to put it another way, 24 degrees up from level?
If I'm correct, is this small adjustment likely to make a difference?
I hope this makes sense to you and I'd be glad for your input on this.
Many Thanks.
---------------------------------------------------------------------------------------------------------------
Briantist
Thursday 3 February 2011 7:59AM
Iain Marshall: Is your aerial on the roof?
It is often best to use a signal strength meter to determine the best position for an aerial. It is, after all, the signal that matters.
The "larger" your aerial is the more directional it will be.
---------------------------------------------------------------------------------------------------------------
Thanks for getting back to me.
Aerial (Group A and about 4-5 feet in length I believe) is in the loft at the rear of the house with no other building or big trees nearby in viewable line of sight.
The signal used to be fine on ALL 5 multiplexes up until approximately a couple of months ago, I think, so it's odd that only the commercial multiplexes seem to be affected now. As I said before Mux C/Arqiva A (CH22) is the worst for me but according to digitaluk it should be the highest of the 3 commercial Muxs and have a 'Served' strength of 85 whereas MuxA/SDN (CH25) is 80 and MuxD/Arqiva B (CH28) should be the worst at 71. Surely something is amiss there? Why is this and can you confirm digitaluk's info is correct?
With me Mux C/Arqiva A (CH22) is the lowest followed by MuxD/Arqiva B (CH28) and MuxA/SDN (CH25). How come the signal strength order of the commercial Muxs that I'm receiving differ to that stated on digitaluk?. Mux1/BBC A (CH26) & Mux2/D3&4 (CH23) have the highest signal strengths and are fine 90+% of the time.
Why do the 3 commercial Muxs broadcast at a lower power compared with Mux1/BBC A (CH26) and Mux2/D3&4 (CH23)?
Why can't they ALL be the same?
Is it because of interference problems with neighbouring transmitters or is it just a case of that they can't afford the equipment necessary for a higher signal strength
Anyway, getting back to what you said in your reply (Thursday 3 February 2011 7:59AM), YES it maybe best to use a signal strength meter, but I don't have one. If I did, I'd use it.
So, PLEASE can you tell me if am I applying the given data on the websites I mentioned in my first post (Thursday 3 February 2011 4:35AM) CORREECTLY or NOT?
Have I got the correct bearing? Should I be subtracting 3 degrees to make it 69 degrees, should it be 72 as listed on digitaluk or should I be adding 3 degrees and therefore pointing my aerial at 75 degrees?
Have I got the this Inclination business correct or does that not matter?
Also, why, on the digitaluk website for stockland Hill from my address "http://www.digitaluk.co.uk/postcodechecker/main/trade/EX2+4LX/38/0/1uu98hm9f6unfhjbiqo1p42h84" are there so many changes to the signal strength of the 3 commercial Muxs (MuxA/SDN (CH25)/MuxD/Arqiva B (CH28)/MuxD/Arqiva B (CH28)) during 2012/13? Before my first post, in your reply on Wednesday 19 January 2011 8:17PM to George Baker, you stated that "the commercial multiplexes will be at the low power levels until 2012".
According to digitaluk, ALL Muxs are at the highest strength (Served) that they will ever be NOW, EXCEPT MuxD/Arqiva B (CH28) which increases from 71 to 84, but then later in 2012 following a "COM late power-up" change, MuxA/SDN (CH25), MuxD/Arqiva B (CH28), MuxD/Arqiva B (CH28) reduce from 80/85/84 to 59/58/61, then later again in 2012 to 53/53/56 and then in 2013 there are two more changes listed making them 53/52/56 then finally 53/52/55. The signal strengths of these Muxs look like they are going to get WEAKER, NOT STRONGER. Can you confirm?
I apologise for this being so very long, but I wanted to give you as much info as possible.
I would very much appreciate your input on these points.
Many thanks.
| link to this comment |
Hi Briantist,
thanks for getting back to me again, but is "Please move your aerial to the roof" ALL the advice you can give me?
Yes, I guess putting it on the roof MAY help, but unfortunately, I can't afford to pay someone just to move the aerial to that location and it's too dangerous to do it myself. I was thinking of attaching it to the outside wall of the house as high up as I can, but haven't got around to it,yet, and anyway, as far as I'm concerned, I shouldn't have to move it anyway.
ALL NEW cabling and connectors were used when the NEW AERIAL was fitted back in MAY 2009 and EVERYTHING was 100% fine up until a couple of months ago.
If everything was fine for 18 months or so, what's changed to lower the signal strength of the commercial Mux's? Has anything changed at the transmitter that www.digitaluk.co.uk have not listed? Is there a problem with the commercial Mux's that no-one seems to know anything about?
PLEASE can you just inform me as to which bearing I should be pointing my aerial and whether I've got this INCLINATION thing correct.
Even if I eventually HAVE to move my aerial outside, I will STILL need to know if I've interpreted this information CORRECTLY so I can position it properly, but before I waste time and money on moving it outside, I'd just like to check that I've got my aerial setup properly for it's current location in the loft and THEN I can decide whether or not it is actually necessary to move the aerial outside.
Many Thanks.
PS.
Could you, if you are able, PLEASE answer the other questions that I asked you?
Why do the 3 commercial Muxs broadcast at a lower power compared with Mux1/BBC A (CH26) and Mux2/D3&4 (CH23)?
Why can't they ALL be the same?
Is it because of interference problems with neighbouring transmitters or is it just a case of that they can't afford the equipment necessary for a higher signal strength?
Also, why, on the digitaluk website for stockland Hill from my address "http://www.digitaluk.co.uk/postcodechecker/main/trade/EX2+4LX/38/0/1uu98hm9f6unfhjbiqo1p42h84" are there so many changes to the signal strength of the 3 commercial Muxs (MuxA/SDN (CH25)/MuxD/Arqiva B (CH28)/MuxD/Arqiva B (CH28)) during 2012/13? Before my first post, in your reply on Wednesday 19 January 2011 8:17PM to George Baker, you stated that "the commercial multiplexes will be at the low power levels until 2012".
According to digitaluk, ALL Muxs are at the highest strength (Served) that they will ever be NOW, EXCEPT MuxD/Arqiva B (CH28) which increases from 71 to 84, but then later in 2012 following a "COM late power-up" change, MuxA/SDN (CH25), MuxD/Arqiva B (CH28), MuxD/Arqiva B (CH28) reduce from 80/85/84 to 59/58/61, then later again in 2012 to 53/53/56 and then in 2013 there are two more changes listed making them 53/52/56 then finally 53/52/55. The signal strengths of these Muxs look like they are going to get WEAKER, NOT STRONGER. Can you confirm?
| link to this comment |
Hi,
I apologise for copy and pasting so much in my post of Thursday 3 February 2011 1:41PM. This was an accidental mistake, but the first part of my last post, (before the PS) is NOT COPY AND PASTED. I only copied and pasted the bit after.
The reason being is that I've asked you several questions, (long-winded but with as much info as possible, because I believe that the more info someone can provide the better the chance of getting the help that you require), BUT, unfortunately for me, you STILL haven't actually answered anything that I've asked.
In your first reply, you asked ME a question, to which I gave you an answer. Then in your second reply just a one line statement.
So, I will try ONCE more and keep each question as short and concise as I can.
1. Please can you confirm the bearing that I should be pointing my aerial. Should it be 69, 72 or 75 degrees or something else?
2. The inclination at my address is approx 66 degrees.
Does that mean that I should have my aerial at an angle of 66 degrees from upright or put another way, 24 degrees up from level?
3. You say that the commercial Mux's are on lower power until 2012. However www.digitaluk.co.uk shows that ALL muxs are on the highest power output that they will be NOW, with what seems like, if I'm interpreting their info correctly, the possibility of reduced power reaching my location from the 3 commercial Mux's lowering several times during 2012/13. Your statement and digitaluk's info appear at odds with each other.
Can you please confirm the situation?
4. Why are the 3 commercial Mux's broadcast on a much lower power output compared to Mux 1/BBC A and Mux 2/D3&4?
5. Is there a reason why can't they ALL be the same?
6. Do you have or can you find out if there is an explanation as to why ALL 5 Mux's have been OK for approx. 18 months (from Digital Switch-over in May 2009 until end of November or early December 2010), but now the 3 commercial Mux's, especially Mux C/Arqiva A (CH22),is so erratic with it's signal power level?
Many Thanks.
| link to this comment |
Hi Brian,
Thanks for your answers.
Just a little clarification, if you can please?
1. Phil Wallace from Sherborne, earlier in this thread, (see his posts and your replies dated from Friday 7 January 2011 2:01PM through to Saturday 8 January 2011 12:31PM) asked if the 248° to Stockland Hill from his location is based on TRUE NORTH i.e. a map bearing or should he adjust for Magnetic Declination. You told him to subtract 3° thus using the bearing of 245°.
Based on that theory, I would like to clarify as to which is the correct bearing for me to use.
Should I also subtract 3° from the bearing that you just gave me thus using a bearing of 69° instead of 72°?
2. "The aerial must be mounted at no parallel to the ground".
Do you mean that the aerial MUST NOT be mounted parallel to the ground?
If that's the case, as I don't have a signal strength meter, I'm guessing that the best angle would have to be found by a bit of trial and error testing?
6. I don't quite see how a fault at my end would possibly affect reception to such an extent on Mux C/Arqiva A (CH22) that I loose picture completely on some occasions but be perfectly OK to watch on others whilst also NOT affecting the signal level from the 2 PSB Mux's at all and barely on the the other two commercial Mux's?
Many Thanks.
| link to this comment |
Hi Brian,
thanks for the clarification on 1 & 2.
My point 6 just seems to be strange one, so, who really knows why it happens with no consistency in time of day or day of the week. I'm guessing, no-one can be 100% sure.
Anyway, I'll now test to see if there is any difference by moving aerial to 69° instead of 72° and monitor using my DVR's own signal strength meter and also double check the connections and cabling for any major bends/kinks/dodgy connectors.
If there is no or little improvement I guess, eventually, I WILL have to move the aerial outside.
Thanks, Brian, for your help and advice. We got there in the end.
| link to this comment |
Hi Brian,
sounds like I was unfortunate to catch you when you were NOT at your best. I hope your cold goes soon so you'll be firing on all cylinders again.
| link to this comment |
Hi Noman,
PC/Wireless Lan interference could well be part of the problem. However, the area I live in seems to have lots of wireless signals coming from what appears to be every direction. I use wireless in my home too, and wherever I position my PC/USB Wireless Adapter and Modem/Router, I get several other Wireless Routers/Access points showing up. So, for this reason alone, I think moving my aerial around the loft is unlikely to help.
If other wireless devices are possibly causing interference, then this is only likely to get worse over time as more and more people use devices that require wireless networking/Internet access. Having said that, TV signals are in the MHz (Megahertz) spectrum (Stockland hill ranges from 481.8 to 538.2MHz) whereas wireless computing usually uses the GHz (Gigahertz) spectrum (2.4GHz or occasionally 5GHz) so, I don't believe that they should cause any conflicts, but I could be wrong on that.
Also due to my location and neighbouring houses, (I live in terraced road), moving the aerial elsewhere in the loft is not practical as I would be introducing many walls between the aerial and the outside world. Currently, I only have my own slate roof in the way.
Pointing my aerial directly though a wall instead if the roof is not possible either because the nearest outside wall is almost parallel to the direction that I need to point the aerial. The next house in the terrace gets in the away again too if I were to try a different wall.
I believe that I currently have my aerial in the optimum place that I can put a loft mounted aerial. That's why I put it there in the first place.
Anyway, Noman, thanks for your advice. It may not help me, but it may help someone else.
| link to this comment |
Hi Brian and Phil Wallace,
I've just found the following document at:--
http://www.digitaluk.co.u….pdf
On page 3 it says that the www.digitaluk.co.uk postcode checker, not only provides customers with information, but also provides installers with:
UHF Frequency channels used through switchover and beyond.
Required aerial groups.
Transmission powers for pre and post switchover.
Compass bearing direction and distance from address to transmitter.
It's that last point that caught my eye "Compass bearing".
If that is how they list the bearings, neither I nor Phil Wallace need to correct the bearings stated. I should still use 72° and he 248°.
Just thought I'd let you, Phil and anybody else know that the bearings stated are Compass bearings and not map bearings so no adjustment is needed.
| link to this comment |
Hi Brian,
So, I SHOULD use 69° and NOT 72° after all then!
It is, obviously, a bit confusing when you see the same bearings listed on two independant sites and one says compass bearing and the other a grid/map reference.
Perhaps someone, probably best if it was you, could let digitaluk know that, despite them having the same bearings listed as you do, their bearings are ALSO grid/map bearings and NOT Compass bearings.
They should then, therefore, inform people of this fact and give instructions to people as to how to work out the Magnetic Declination for their location and how they should apply it, or, change all of their bearings to include Magnetic Declination. I guess that it would be easier to do the former as I doubt the whole of the UK has a 3° difference, as I do, and even if they did, they might have to add it on instead of subtracting it.
Anyway, I'm inclined to accept your information rather than digitaluk's now.
Thanks for the clarification.
| link to this comment |
Page 1
Thursday 3 February 2011 4:35AM
Exeter
Hi,
I am in Exeter .
I have been having problems with the multiplexes on CH22 and CH28 (STOCKLAND HILL). CH22 is the worst where sometimes I've had no picture at all or a slideshow with sound stuttering. Even when it is perfectly watchable, if I'm recording a TV station, from ANY of the 5 multiplexes, the programs on multiplex CH22 start breaking up again. Any ideas as to why this is?
Also, according to www.digitaluk.co.uk/postcodechecker/, it gives a bearing of 72 degrees to Stockland Hill from my address and the website www.magnetic-declination.com/ states a magnetic decination of 2 degrees 41 minutes WEST, Declination is NEGATIVE and Inclination is 65 degress 43 minutes.
Therefore, should I be pointing my aerial at approx. 69 degrees instead of 72 and having it at an angle of approx 66 degrees from upright or, to put it another way, 24 degrees up from level?
If I'm correct, is this small adjustment likely to make a difference?
I hope this makes sense to you and I'd be glad for your input on this.
Many Thanks.